FI117364B - Energy production arrangement - Google Patents

Description

117364

Energy production arrangement

Field of the Invention 5

The present invention relates in particular to an arrangement for the production of small-scale electrical energy. The invention relates to a device for generating electrical energy having a first piezo element, a second piezo element located on the same substrate as the first piezo element, which piezo-10 elements are arranged to convert mechanical energy into electrical energy varying according to mechanical energy variations. based on the electrical energy produced by the first piezo element, and an energy storage to store the electrical energy. The invention 15 relates to a system comprising a second piezo element for producing electrical energy having a first piezo element, arranged on the same substrate as the first piezo element, arranged to convert mechanical energy into electrical energy having a level of electrical energy varying according to mechanical energy. a control block for generating measurement data based on the electrical energy produced by the first piezo element, and an energy storage for storing electrical energy. The invention also relates to a ring comprising a device for generating electrical energy having a first piezo element to the same piezo element:. A second piezo-element mounted on a substrate, the piezo-elements being arranged to • “Y convert mechanical energy into electrical energy of electric energy γ; the level varies according to variations in mechanical energy, and a control block connected to the first piezoelement element to generate measurement data based on the electrical energy produced by the first piezo element, and an energy storage 30 for storing electrical energy. The invention further relates to a method for generating electrical energy, wherein mechanical energy is converted into electrical energy in a first piezo element and a second piezo element in the same substrate as the first piezo element, with varying levels of electrical energy 35, generating measurement data based on the electrical energy * * Y · produced by the first piezo element, and using an energy storage to store electrical energy.

2,117,364

Background of the Invention

There are many devices that require small-scale power generation because it can be impossible or at least very difficult to arrange power supplies such as batteries for such devices. Some non-limiting examples of such devices include tires having a sensor for measuring or detecting certain tire properties such as air pressure, temperature, etc. and product sensors affixed to the packaging of the product for example to indicate conditions that have affected the product during transportation and / or storage. during.

Such sensors are often implemented using wireless transmission technology, i.e., sensors transmit data, for example, by radio waves. Such sensors are commonly referred to as Radio Frequency Identification (RFID) sensors. They require electrical energy to transmit or receive data to or from a reader. In some embodiments, the energy required by the RFID sensor is generated in the reader in the form of an electromagnetic field, however, the distance between the reader and the RFID sensor must be kept relatively small and the available RFID sensor energy is very small.

«· * • · • *» · ·

Efforts have also been made to generate electrical energy for the device by means of a piezo generator. A piezo generator is a device that converts mechanical energy into electrical •. ·. 25 energy by means of a piezoelectric converter such as a piezoelectric membrane.

* · ♦ a * Y However, the power level produced by such a piezo generator has been quite · ::: low for some applications that use RFID sensors.

• * • *

Summary of the Invention:.: V 30 · * ·

It is an object of the present invention to provide an arrangement for producing energy more efficiently than in the prior art. The invention is based on the idea that the same piezo generator which produces mit-Y * background data also produces the energy required to operate the measurement unit which studies the measurement data to produce a signal for more accurate analysis of the measurement data. it collects the piezoelectric energy at the stage where the voltage level is at or near the peak. More specifically, the device of the present invention is essentially characterized in that the control block further comprises: , arranged to initiate the storage of electrical energy produced by the second piezo element when a peak of electrical energy is detected.

The system of the present invention is essentially characterized in that the control block comprises: - a comparator (4.2) for examining measurement data to determine the peak electric energy generated by the first piezoelement element (2) and generating a trigger signal for detecting the peak, connected to a comparator (4.2) for transmitting a trigger signal to a control unit (4.4, V1) arranged to initiate the storage of electrical energy produced by the second piezo element (2) when a peak electrical energy is detected.

The ring of the present invention is essentially characterized by the fact that the control block comprises: - a comparator for studying measurement data at the peak of electrical energy. 25 for pulling and generating a trigger signal for catching the peak value,? Y, * · * * ;;; - a control unit coupled to a comparator for transmitting a trigger signal to a control unit arranged to initiate the storage of electrical energy generated by the second piezo element when a peak value is detected.

:: i :: 30

The method according to the present invention is mainly characterized in that the method also comprises the following steps: - studying the measurement data to determine the peak value of the electric energy in order to "" · *, · ": 35 - storing in the energy storage the electrical and 4,117,364 - directing the operation of the energy storage to trigger the storage of the electrical energy produced by the first piezo element when a peak electric energy is detected.

According to an exemplary embodiment of the present invention, there is provided a system using two piezo generators, a measuring piezo generator for a sensor and a power piezo generator for generating energy, and wherein a measuring piezo generator is also used to generate energy for a measuring and control circuit.

10

The invention provides advantages over prior art methods and systems. In the device and system of the present invention, the electrical energy generated by the piezo generator can be utilized more than in the devices and systems of the prior art. Thus, it is possible and sensible to use the piezo generator as a power source in many applications where it has so far not been possible. The invention makes it possible to avoid the use of batteries and other similar energy sources in many applications, particularly RFID applications.

DESCRIPTION OF THE DRAWINGS f. The invention will now be described in more detail with reference to the accompanying silicon * * * drawings in which 4 «« * 4. Fig. 1 illustrates an exemplary embodiment of the present invention in a simplified block diagram, Fig. 2a illustrates an example of a control block of the device of the present invention in a simplified block diagram, Fig. 2b. Figure 3 illustrates an exemplary circuit of a storage block of the control block of Figure 2a, Figure 3 illustrates an example of the output stage of the present invention ·: * · *: 35 in simplified block diagram, • 4 • 44 4 44 • 4 5 117364 Figure 4a examples of control block waveforms when the ring is subjected to different loads, Figure 4b shows examples of output waveforms, Figure 5 shows an example of a system according to the present invention in a simplified block diagram, and Figure 6 shows an example of inserting a piezo generator into a ring 7b illustrates the position of the ring with respect to the curve of FIG. 7a.

DETAILED DESCRIPTION OF THE INVENTION Block diagram of piezo generator 20

The piezo generator 1 consists of four functional parts, some of which may be physically connected to one another. The measuring piezo generator produces oh, ··. feeder power to operate the output stage. The ice waveform of the piezogenerator • 9 «is used to measure timing information. The power piezo /. * 25 generator produces high voltage pulses with high impedance and converted by 9 9 *: · γ switching output to low voltage. The measuring piezo generator and power piezo generator may be separate or may be formed on the same piezo platform. The piezo-substrate may be etched to provide wiring to connect the voltages produced by the piezo-elements 2, 3 to the other wiring. Similarly, the controller and the output stage may be separate or at the same time on the circuit board.

The block diagram of Figure 1 illustrates the main blocks of the piezo-generator 1 according to the exemplary embodiment of the present invention. The piezo-generator 35 comprises a first piezo element 2 and a second piezo element 3. The first piezo element 2 is used as a sensor, i.e. The measurement information may include information about tire pressure, tire temperature, wheel load, etc. The first piezo element is connected to control block 4, which receives the measurement data from the first piezo element 2. When when the external force stretches or compresses the first piezo-element 2 (i.e., the shape of the first piezo-element 2 changes), the voltage passing through the first piezo-element 2 changes, which can be used by control block 4 as a measurement data. The electric energy produced by the first piezo element 2 is used to supply electric energy for the operation of the control block 4. The operation of the control block 4 is described below in this application.

The arrows R in Figure 1 illustrate the direction of the energy producing stress in the piezo elements 2, 3.

The second piezo element 3 is used as an energy source to supply energy to other devices that may be connected to the piezo generator 1. The second piezo element 3 is also affected by an external force which causes variations in the shape of the second piezo element 3. As a result of these deformations, the second piezo element 3 generates electrical energy which is supplied to the output block 5. The output block 5 converts this energy to a suitable form, as will be described below in this application.

»• I • · • *

The first piezo element 2 and the second piezo element 3 may be separate * · ...: or attached to a common base 7. Similarly, the control block 4 and the output block 5:. 25 may be separate or on the same substrate, for example on the same circuit board. In the embodiment, where the piezo generator 1 comprises at least the first 2 and the second piezo element 3, these must be assembled such that the stresses in the first 2 and the second piezo element 3 behave in substantially the same manner.

30 Controls • ·· • · · **

Figure 2a shows an example of a control block 4. The control block 4 has three main functions. Firstly, the combination of the Dormant Sleep 4.1 and the storage block - *: * cl 4.6 provides power for comparison to block 4.2 and *: * ': 35 single swing block 4.4. Second, the reference block 4.2 detects the correct trigger times by deriving them from the supply block input signal 4.9. Third, the output pulses produced by the reference block 4.2 are used to trigger the single-wing block 4.4 7 117364. The storage block input signal 4.9 is formed from the voltage produced by the first piezo element 2 and rectified from the full wave rectifier 4.1. Compare the block input signal n 4.3, the trip trigger block input signal 4.8. and the voltage levels of the storage block input signal 4.9 are limited, if necessary, in the storage block 4.6.

When the storage block input signal 4.9. begins to decrease (first trigger point), control block 4.2 Triggers a single trigger block 4.4, which may consist of, for example, MOSFETs. The reference output signal 4.7 generated by block 4.2 is used to trigger a single trigger block 4.4 which generates a control signal 4.5 (pulse) to the output block 5 to store energy from the second piezo element 3. The storage block input signal 4.9 drops to substantially zero and then begins to rise again. At the next peak level (second trigger point), the reference block 4.2 again taps the single trigger step 4.4 to obtain a control signal 4.5 (second pulse) for the output block 5 to store energy from the second piezo element 3. In other words, the output block 5 can store energy from the second piezo element.

When the control block 4 is made of low-delay components, it can consume less than 1 μΑ of resting current. Figure 2b shows an example of a circuit of a storage block 4.6. The Zener diodes D3, D4 provide certain reference voltage levels · · * ·. to block 4.2 and to the single trigger block 4.4. The purpose of the diodes D1, D2 is to isolate the reference block input signal 4.3 from the single-trigger input signal 4.8. In some embodiments, the separation may not be required, so the same • *. The supply voltage may be connected to both the reference block 4.2 and the single-trigger 'Y block 4.4. With a voltage coming from rectifier 4.1 through diode D1 * ;;;; orbital capacitor C2. Capacitor C2 stores enough energy to operate the output stage 5 as it is Heated. The advantage of this circuit is that you do not need any power or anything else to start the operation: J .: 30 circuits. In the arrangement according to the invention, energy production is started from the first movement of the first * [*] piezo element 2.

• · *

Fig. 4a shows some waveforms of the control block 4. Curve 401 provides an example of the tension of the first piezo-element 2. The voltage waveform from the second *: **: 35 piezo element is very similar to the voltage waveform, but after a full wave rectifier, the negative voltages are converted to positive voltages. For this reason, positive peaks of 8,117,364 storage block input signals 4.9 are detected. The first trigger point is shown by arrow 402, the second trigger point by arrow 403, the third trigger point by arrow 404, and the fourth trigger point by arrow 405. 404, 405. From the waveform 406 of the controller supply voltage, it can be seen that when the first piezo element 2 begins to generate electrical energy, the voltage begins to rise until the voltage is limited by the zener diode D3. When the output block 5 is adjusted to start 10 energy storage (at the first trigger point 402), the controller supply voltage drops near zero and begins to rise again until the zener diode D3, D4 limits the voltage at a certain level. At the beginning of one pulse (at the second trigger point 403), the voltage drops to zero or near zero. The capacitor C1 stores sufficient energy for operation of the reference block 4.2, although the voltage 15 decreases during the output pulses of the single-trigger block 4.4.

Fig. 4a shows another curve 411. It shows a second example of the tension of the first piezo element 2 when the load on the ring is lower and / or the air pressure of the ring is higher than that of the curve 401. The trigger positions in this example are shown by arrows 412, 413, 414, and 415, respectively. Curve 416 illustrates the waveform of the controller supply voltage. ***. at the output nodes of the full wave rectifier 4.1, and the curve 417 shows the pulses generated by the trigger block 4.4 at the trigger points 412, 413, 414, 415.

* * ·. . The output block 5 comprises an assembly of a dummy sleeper 5.1, a coil L1, a FET transistor V1, and an output capacitor C3. The output block cycle consists of five steps. Initially, the FET transistor V1 is disconnected. As the second piezo element 3 is stretched or contracted, the voltage of lin- *** 5.4 begins to rise. Since both the first 2 and the second piezo-element 3 are fixed close to each other and preferably on the same substrate, the first piezo-element 2 also stretches or contracts accordingly. Then V also starts to increase the voltage of the supply block 4.9 of the storage block. When the voltage of line 5.4 *: *: 35 is substantially at its maximum value, the supply block 4.9 of the storage block is also at or near its maximum value. In this case, the single-trigger block 4.4 of the control block 4 raises the GATE signal (control signal 4.5 according to Figure 2) to 9 117364, which turns on the FET transistor V1. Current begins to flow through coil L1 and FET transistor V1 to output capacitor C3. The voltage on line 5.4 also starts to drop. The inductance of the coil L1 limits the current rise rate. When the voltage of line 5.4 reaches substantially zero, most of the energy produced by the second piezo element 5 is stored in coil L1. The current is then applied to diode D5 and the current begins to decrease. Energy is transferred from coil L1 to capacitor C3. Capacitor C3 acts as a reservoir of energy produced by the second piezo element. Energy can be further supplied from output 5.2 to another device 10, for example a transmitter (Figure 5). It is also possible for $ 10 to use the battery instead of or alongside the C3 capacitor. Shortly after the current has substantially reached zero, the signal propagating in the GATE line drops, which turns off the FET transistor V1, and the circuit is reset. The GATE REF signal from control block 4 is connected to the second output of the rectifier. However, the GATE REF signal can also be connected to, for example, the collector of FET transistor V1. Optionally, capacitor C4 can be coupled to diode D5 to limit the maximum value of the rectified voltage generated by the second piezo element 3. The optional capacitor C4 is effectively coupled in parallel with the capacitor of the second piezo-element 3. The diode D6 and the zener diode D7 limit the voltage peaks 20 in the coil L1 and the FET transistor V1 in the event that the FET transistor V1 is switched off while there is still current flowing through the coil L1. The Zener diode D7 and the signal amplitude of the GATE line limit the maximum output voltage. One of the:% reforms circuit is a FET transistor switch V1 and below the upper and above the switch with respect to the output 5.2 and lower switches;. ... 25 go to reel L1. The circuit has at least two benefits. First, because the * · · "V outputs at n output 5.2 are relatively small, the signal level in the GATE- * ;;; line can also be low. Secondly, the circuit does not need any control over the duty cycle.

• e 'It is sufficient to set the pulse of the GATE line long enough to transfer substantially all available energy from the second piezo element 3 to the output 5.2.

• · • «

The voltages generated by the piezo-elements 2, 3 are of variable nature, due to variations in the mechanical forces acting on the piezo-elements 2, 3. As a result of these fluctuations, the voltage has several local * 35 maximum and minimum values. The different maximum values are not necessarily the same, but 0 · ί may differ. Therefore, in the description of the invention, the word maximum 10 117364 does not necessarily mean a general or absolute maximum value of the voltage but a local maximum value, i.e. the peak value, after which the voltage begins to decrease.

Figure 4b shows some waveforms of the output block 5. Curve 408 shows the rising edge of a pulse generated by 5 single-trigger blocks 4.4 at one of the trigger points 402, 403, 404, 405 (Figure 4a). Curve 409 shows the voltage waveform of line 5.4 at the output nodes of the output block 5 full-wave rectifier 5.1, and curve 410 represents the current flowing through coil L1.

Although the output voltage of the output block 5 is limited, the voltage supplied from the second piezo element 3 is not limited in this exemplary embodiment. On the other hand, it may be necessary to limit the supply voltage to the controller, as described in the description of the operation of the control block, in order to avoid damaging the electronics of the control block, especially the reference block 4.2.

15

Piezo generator configuration

There are several alternatives for the use and configuration of the piezo generator of the present invention. The first piezo element 20 must be assembled so that the measurement data it provides is appropriate for the application and the energy produced by the first piezo elements 2 and 2 3 is also maximized. In the embodiment, «:»: T: where the piezo generator 1, consisting of at least the first 2 and the second * 3 piezo elements, is mounted inside the ring 6, the piezo elements must be mounted side by side in the direction of rotation of the ring 6. The arrows R in Fig. 1 indicate the direction of rotation, which also indicates the direction of tension or contraction of the piezo elements 2, 3.

• «♦ · · *»

In the exemplary embodiment of Figure 6, the piezo generator 1 is mounted within the ring-30. The first 2 and the second 3 piezo elements are fixed or * · · otherwise made on the same substrate 7. The substrate 7 is made of, for example, rubber or other elastic material which allows tension and contraction of the piezo elements 2, 3. The base 7 is mounted on the inner surface of the tire 6 * * ", preferably on a surface 35 opposite to the tire tread 6.1. The base 7 is secured to the ring 6, for example by gluing. The control block 4 and output block 5 of the piezo-generator 1 may be assembled more freely that the control block 4 and the output block 5 are assembled 11 117364 on the same base 7 as the piezo elements 2, 3. The control block 4 and the output block 5 can be assembled even outside the ring, for example the rim 9 where the ring 6 is mounted. The currents 5 between the 3 and the other parts 4, 5 of the piezo generator 1 are not very strong, the lengths of the conductors passing between the piezo elements 2,3 and the control block 4 and the output block 5 should be kept as short as possible to minimize power losses.

Figure 7 shows an example of the waveform of the voltage produced by the first and second piezo elements. Figure 7 shows the rotation shells of the ring 6 with respect to the waveform of Figure 7a. The reference numerals 701-704 of Figure 7a refer to the rotation angle of the ring 6 relative to the centerline of the piezo elements 2, 3 in the ring. The same reference numerals are also shown in Fig. 7b, which shows the relationship between the rotation angles and the corresponding stress of the piezo elements 2, 3. Reference numerals 701, 703 denote maximum curvature points, reference numeral 702 at the contact area (in the area where ring 6 and surface 8 contact each other) and reference numeral 704 in the neutral area of ring 6 (in the area where ring 6 does not touch the surface). The side profile of the ring 6 is generally circular in the neutral region.

20

As the ring rotates on surface 8, the tire will occasionally be at the point where the piezoelectric: ***: elements 2, 3 begin to stretch or contract. At this point, the area of ring 6, M *. *: * », Where the piezo elements 2,3 are located, comes into contact with the surface 8.

Since the ring 6 is normally subjected to a certain weight, for example, its driving; ... 25 the weight of the tire (not shown) to which the tire is attached, this range will change to "V" shape. The extent of the changes will depend, among other things, on the tire's internal air pressure, tire load and tire temperature. The changes in the position of the piezo elements 2, 3 also cause forces to be applied to the piezo elements 2, 3, whereupon the piezo elements 2, 3 can generate electrical energy 30. In the exemplary embodiment, the force applied to the piezo elements 2, 3 can be deduced 7a and also based on the waveform of Figure 7a.

«« »*: ** Manufacturing piezo element 35 ί /. · The following describes the example of piezo elements 2, 3

making. A piezo-plate which is, for example, silver-plated MSI

12 117364 1-1004346-0 PVDF type, cut into pieces. The direction of the stretching of the tracks on the Pietsolve is marked. The electrodes of the piezo elements 2, 3 are connected to opposite sides of the pieces. The electrode contact surfaces are short-circuited from one side to the other by making small holes through the membrane. The piezo elements 2, 3 are fastened to the support 7.

Pietsokytkennät

Piezoelectric connections include, for example, flexible metal wire, 10 braided copper wire, tin and electrically conductive silver paint. The mechanical coupling can be reinforced with heat-shrinkable insulation and adhesive.

Measuring System 15 Figure 5 shows an example of a system having a piezo generator 1 according to the present invention. In this example, the system is intended to measure the air pressure of the ring 6 and to generate an alarm if the air pressure falls below a certain threshold. The system includes a piezo-generator 1, a transmitter 10, a receiver 11 and an analysis block 12. The piezo-20 generator 1 is mounted on the inner surface of the ring 6. The transmitter 10 may also be mounted on the inside of the tire 6 or on the rim 9. The receiver 11 s "!: is mounted on the vehicle on which the tire 6 is mounted. The receiver is coupled to the analysis block 12.

#: 25 In operation, the piezo generator 1 provides measurement data and energy to an external * * · * “V device, such as transmitter 10. In this embodiment, the first piezo element 2 provides measurement data and also energy to control block • m 4. Second piezo element 3 provides energy to transmitter 10 and other components (not shown) coupled to the piezo-30 generator 1 (inside ring 6 or rim 9). An output stage 5 ··· ♦ output 5.2 is coupled to transmitter 10 to supply energy for operation of transmitter 10. The output of the single trigger block 4.4 can be connected to the input of transmitter "··. 10 to input measurement data, i.e. pulses, to transmitter 10.

• · Transmitter 10 transmits pulse information, e.g. pulse timing information, to receiver 11. Transmit wirelessly, for example, 0 ·! through. The receiver 11 receives the data and transmits it to the analysis block 12. The analysis block 12 can analyze the conditions of the ring 6 based on the pulse timing information. The analysis block 12 may comprise a table or other data for use in analysis.

Transmitter 10 generally does not require a battery or other source of energy when generating energy according to the present invention with a piezo generator 1. Thus, the invention makes it possible to implement e.g. RFID technology in many fields.

Although it was described above that the piezo generator 1 comprises two piezoelectric elements 2, 3, the invention is not limited to such embodiments. For example, the piezo generator 1 comprises only one piezo element which can be used to generate energy for the control block 4, the output block 5 and also for other parts to which the piezo generator 1 is connected. In this embodiment, the output block 3 is also connected to the piezo element. Additional components, such as diodes, may be required to isolate the supply voltages of the various parts of the piezo-generator 1. It is also possible that the piezo generator 1 may comprise more than two piezo elements.

• · ♦ • 1 • · 4 »» II · m · 4 »44 4 4 4 4 • 4 4 4 · 4 4 4 4 ·· 4 m 444 4 4444 444 4 4 4 4 444 4 4 4 4 4 4 4 • 44 ·· ♦ • 4 4 4 • 4 4 • 4 • 44 4 444 # 44 4 4 * 4 44 4 4 4 4 4 4 4 4 4 4 4 4 «• 4

Claims (17)

Apparatus (1) for the production of electrical energy, comprising: - a first piezo element (2); 5. a second piezo element (2) placed on the same support with the first piezo element (2), which piezo elements (2, 3) are arranged to convert mechanical energy to electrical energy, the level of the electrical energy varying according to variations of the mechanical energy, - a control block (4) coupled to the first piezo element (2), comprising a measuring unit (4.1) for forming measurement information ρέ the base of the energy generated by the first element (2), and - an energy supply (L1) for storing the electrical energy, characterized in that the device (1) further comprises - a comparator (4.2) for examining the measurement information for investigating the peak value of the electrical energy generated by the first piezo element (2) ooh to form a trigger signal from the recording of the peak value, and - a control unit (4.4, VI) which is co pplad to the comparator (4.2) to transmit the trigger signal to the control unit (4.4, V1) arranged to initiate storage of the electrical energy generated by the second piezo element (3) after the peak value of the electrical energy. ··. has been discovered. ** · Device according to claim 1, characterized in that the control unit (4.4, V1) comprises a pulse generator (4.4) to form a pulse after the peak value: * V has been detected, the control unit (4.4, V1) being adapted to control energy- »» ·; · | the stock (L1) to store the energy generated by the second piezo element (3) under the puis. Device according to claim 2, characterized in that the control unit (4.4,: * [*: V1) comprises an FET transistor (V1) for conducting it by the second piezo-V. the element (3) produced the energy for the energy supply (L1) during the pauses. »« «• • • • 9« 4. Device according to claim 3, characterized in that it comprises an output for supplying the energy produced by the second piezo element (2): [[[: from the device to another device ( 10). 19 117364 Device according to any of claims 1-4, characterized in that the measurement information is the voltage produced by the first element (2). Apparatus according to claim 3, comprising a capacitor (C3) for storing electrical energy, characterized in that the FET transistor (V1) is arranged to conduct energy stored in the energy supply (L1) at different times than during the interruption. to the capacitor (C3). Device according to any one of claims 1-6, characterized in that the energy supply (L1) is a coil. A system comprising a device (1) for producing energy, comprising: - a first piezo element (2); 15. a piezo element (2) disposed on the same support with the first piezo element (2), said piezo elements { 2, 3) are adapted to convert mechanical energy into electrical energy, the level of the electrical energy varying according to variations of the mechanical energy, - a control block (4) coupled to the first piezo element (2) comprising a measuring unit (4.2) to form measurement information on the basis of the energy generated by the first piezo element (2), and. - an energy supply (L1) for storing electrical energy, characterized in that the system comprises an additional * * * - a comparator (4.2) for examining the measurement information to investigate • *; The peak value of the electrical energy generated by the first piezo: * V element (2) and to generate a trigger signal from the recording of the peak value, - a control unit (4.4, Vt) coupled to the comparator (4.2) to - transmit the trigger signal to the control unit (4.4, V1) arranged to initiate storage of the electrical energy generated by the second piezo element (2), after the peak value of the electrical energy has been detected. 9. A system according to claim 8, characterized in that the control unit (4.4, V1) comprises a pulse generator (4.4) to form a pulse after the peak value has: [[[: detected , wherein the control unit (4.4, V1) is adapted to control the energy supply (L1) to store the energy generated by the second piezo element (2) during the pause. System according to claim 8 or 9, characterized in that the control unit 5 (4.4, V1) comprises a FET transistor (V1) for directing the energy produced by the second piezo element (3) to the energy supply (L1) under the puis. System according to claim 10, characterized in that it comprises an output for supplying the energy 10 produced by the second piezo element (2) from the device to another device (10). System according to claim 10, characterized in that it further comprises a transmitter (10) for transmitting the measurement information in a wireless manner, and a receiver (11) for receiving the measurement information, and the output is coupled to the transmitter (10). to produce energy for the transmitter (10). System according to any of claims 8-12, characterized in that the measurement information is the voltage produced by the first element (2). System according to claim 10, comprising a capacitor (C3) for storing electrical energy, characterized in that the FET transistor (V1) is arranged to conduct energy stored in the energy supply (L1) to the capacitor (C3). at other times during the pause. • * • ** ϊ. e. 25 System according to any of claims 8-14, characterized in that the energy Y supply (L1) is a coil. ··· • »» · • «* * ψ *** ·· 16. Ring comprising a device (1) for producing energy, comprising: - a first piezo element (2), fixed in conjunction with the inner surface of the ring, 30. one on the same support with the first piezo element (2) placed second Ϋ *: piezo elements (3), which piezo elements (2, 3) are arranged to convert mechanical energy into electrical energy, the level of the electrical energy varying according to variations of the mechanical energy, T * -. a control block (4) coupled to the first piezo element (2), comprising: a measuring unit (4.2) to form measurement information on the basis of the energy generated by the first piezo element (2); and energy supply (L1) for storing the electrical energy, characterized in that the ring further comprises - a comparator (4.2) for examining the measurement information for investigating the peak value of the electrical energy and for generating a trigger signal from the recording of two 5. a control unit (4.4, V1) connected to! the comparator (4.2) for transmitting the trigger signal to the tilt control unit (4.4, V1) which is arranged to initiate storage of the electrical energy generated by the second piezo element (2), after the peak value is detected. 10 A method of producing energy, wherein: - mechanical energy is converted into electrical energy in a first piezo element (2) and on the same substrate with the first piezo element (2) placed second piezo element (2), whose level of electrical energy varies according to variations of the mechanical energy, 15. forming measurement information on the basis of the energy generated by the first piezo element (2), and - using an energy supply (L1) to store the electrical energy, characterized in that in the process further - the measurement information is examined to investigate the peak value of the electrical energy, - electrical energy produced by the second piezo element (2) is stored in .1 2 ··. the energy supply (L1), and • «. ·! ·. - the operation of the energy supply (L1) is led to start storing the electrical energy produced by the first piezo element (2), after the .1 .1 peak value of the electrical energy has been detected. • 1 m ··· t • • · »* • · · • · • 1 • · · *» »· • 1 · ♦ 1 • 1 · *» * · ♦ • · · ·· · • »• 1 · · · * ♦ · • 1 2 · • 1 • »• · m